openwrtv3/target/linux/mediatek/patches-4.4/0073-net-mediatek-fix-stop-and-wakeup-of-queue.patch

From 868eb5a3d0217e1ecdc2f628c6dc4fcd18562a71 Mon Sep 17 00:00:00 2001
From: John Crispin <blogic@openwrt.org>
Date: Tue, 29 Mar 2016 16:41:07 +0200
Subject: [PATCH 73/91] net: mediatek: fix stop and wakeup of queue

The driver supports 2 MACs. Both run on the same DMA ring. If we go
above/below the TX rings thershold value, we always need to wake/stop
the queu of both devices. Not doing to can cause TX stalls and packet
drops on one of the devices.

Signed-off-by: John Crispin <blogic@openwrt.org>
---
 drivers/net/ethernet/mediatek/mtk_eth_soc.c |   37 +++++++++++++++++++--------
 1 file changed, 27 insertions(+), 10 deletions(-)

--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -684,6 +684,28 @@ static inline int mtk_cal_txd_req(struct
 	return nfrags;
 }
 
+static void mtk_wake_queue(struct mtk_eth *eth)
+{
+	int i;
+
+	for (i = 0; i < MTK_MAC_COUNT; i++) {
+		if (!eth->netdev[i])
+			continue;
+		netif_wake_queue(eth->netdev[i]);
+	}
+}
+
+static void mtk_stop_queue(struct mtk_eth *eth)
+{
+	int i;
+
+	for (i = 0; i < MTK_MAC_COUNT; i++) {
+		if (!eth->netdev[i])
+			continue;
+		netif_stop_queue(eth->netdev[i]);
+	}
+}
+
 static int mtk_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct mtk_mac *mac = netdev_priv(dev);
@@ -695,7 +717,7 @@ static int mtk_start_xmit(struct sk_buff
 
 	tx_num = mtk_cal_txd_req(skb);
 	if (unlikely(atomic_read(&ring->free_count) <= tx_num)) {
-		netif_stop_queue(dev);
+		mtk_stop_queue(eth);
 		netif_err(eth, tx_queued, dev,
 			  "Tx Ring full when queue awake!\n");
 		return NETDEV_TX_BUSY;
@@ -720,10 +742,10 @@ static int mtk_start_xmit(struct sk_buff
 		goto drop;
 
 	if (unlikely(atomic_read(&ring->free_count) <= ring->thresh)) {
-		netif_stop_queue(dev);
+		mtk_stop_queue(eth);
 		if (unlikely(atomic_read(&ring->free_count) >
 			     ring->thresh))
-			netif_wake_queue(dev);
+			mtk_wake_queue(eth);
 	}
 
 	return NETDEV_TX_OK;
@@ -897,13 +919,8 @@ static int mtk_poll_tx(struct mtk_eth *e
 	if (!total)
 		return 0;
 
-	for (i = 0; i < MTK_MAC_COUNT; i++) {
-		if (!eth->netdev[i] ||
-		    unlikely(!netif_queue_stopped(eth->netdev[i])))
-			continue;
-		if (atomic_read(&ring->free_count) > ring->thresh)
-			netif_wake_queue(eth->netdev[i]);
-	}
+	if (atomic_read(&ring->free_count) > ring->thresh)
+		mtk_wake_queue(eth);
 
 	return total;
 }